From 9dcb13bf2787bc5249b2499d72e2ddbffad96373 Mon Sep 17 00:00:00 2001
From: Magnus Ahltorp <map@kth.se>
Date: Tue, 22 Nov 2016 14:08:14 +0100
Subject: listpermdb: support 64-bit commit length field Better error handling

---
 test/listpermdb.erl | 53 +++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 43 insertions(+), 10 deletions(-)

(limited to 'test')

diff --git a/test/listpermdb.erl b/test/listpermdb.erl
index 4000971..526ca98 100755
--- a/test/listpermdb.erl
+++ b/test/listpermdb.erl
@@ -9,7 +9,7 @@
 -define(DATA_COMMIT_START_COOKIE, 16#75c2e4b3d5f643a1).
 -define(DATA_COMMIT_END_COOKIE, 16#2b05eed61b5af550).
 -define(INDEX_COMMIT_END_COOKIE, 16#2fb1778c74a402e4).
--define(DATA_FILE_COOKIE, 16#d53551ba539a4252).
+-define(DATA_FILE_COOKIE, 16#99c99d588b1e7983).
 -define(INDEX_FILE_COOKIE, 16#b7e16b02ba8a6d1b).
 -define(DATA_ENTRY_COOKIE, 16#e7c1cdc2ba3dc77c).
 -define(INDEX_NODE_COOKIE, 16#2e0f555ad73210d1).
@@ -100,12 +100,20 @@ printindex(<<Unknown:16/binary, _Rest/binary>>, FileOffset) ->
     error.
 
 printdata(<<>>, FileOffset) ->
+    io:format("reached end of file~n", []),
     {ok, FileOffset};
 printdata(<<?DATA_ENTRY_COOKIE:64, Key:32/binary, 1:16, Length:16, Rest/binary>>, FileOffset) ->
     FileOffset2 = FileOffset + 8 + 32 + 4,
     io:format("data ~p key ~p length ~p~n", [FileOffset, Key, Length]),
-    <<Data:Length/binary, Rest2/binary>> = Rest,
-    printdata(Rest2, FileOffset2 + Length);
+    case Rest of
+        <<Data:Length/binary, Rest2/binary>> ->
+	     printdata(Rest2, FileOffset2 + Length);
+	 _ ->
+	     io:format("data was truncated, remaining bytes: ~p ~p~n",
+                       [size(Rest),
+                        binary:part(Rest, 0, min(size(Rest), 16))]),
+	     error
+    end;
 printdata(<<?DATA_COMMIT_START_COOKIE:64, Rest2/binary>> = Rest, FileOffset) ->
     Padding = case FileOffset rem 4 of
         0 ->
@@ -118,16 +126,41 @@ printdata(<<?DATA_COMMIT_START_COOKIE:64, Rest2/binary>> = Rest, FileOffset) ->
             1
     end,
     io:format("printdata: ~p ~p~n", [Padding, FileOffset]),
-    <<0:Padding/unit:8, CommitLength:32, CommitChecksum:32/binary, ?DATA_COMMIT_END_COOKIE:64, Rest3/binary>> = Rest2,
-    {{CommitLength, CommitChecksum, Rest3}, FileOffset + 8 + Padding + 4, FileOffset + 8 + Padding + 4 + 32 + 8};
-printdata(<<Unknown:16/binary, _Rest/binary>>, FileOffset) ->
-    io:format("unknown byte: ~p at ~p~n", [Unknown, FileOffset]),
-    error.
+    case Rest2 of
+        <<0:Padding/unit:8,
+          CommitLength:64,
+          CommitChecksum:32/binary,
+          ?DATA_COMMIT_END_COOKIE:64,
+          Rest3/binary>> ->
+            {{CommitLength, CommitChecksum, Rest3},
+             FileOffset + 8 + Padding + 8, FileOffset +
+                 8 + Padding + 8 + 32 + 8};
+        _ ->
+            io:format("commit trailer was not correctly formed at ~p, "
+                      ++ "expected padding ~p, remaining bytes: ~p ~w~n",
+                      [FileOffset, Padding, size(Rest),
+                       binary:part(Rest, 0, min(size(Rest), 64))]),
+            error
+    end;
+printdata(Data, FileOffset) ->
+   Unknown = binary:part(Data, 0, min(size(Data), 16)),
+   io:format("unknown byte: ~p at ~p~n", [Unknown, FileOffset]),
+   error.
+
+read_whole_file(File, Size) ->
+    case file:read(File, Size) of
+        {ok, Data} ->
+            RestData = read_whole_file(File, Size),
+            <<Data/binary, RestData/binary>>;
+        eof ->
+            <<>>
+    end.
 
 main([Filename]) ->
     {ok, FileInfo} = file:read_file_info(Filename),
     File = openfile(Filename),
-    {ok, Data} = file:read(File, FileInfo#file_info.size),
-    io:format("read ~p bytes~n", [size(Data)]),
+    Data = read_whole_file(File, FileInfo#file_info.size),
+    io:format("read ~p bytes, file size ~p~n",
+              [size(Data), FileInfo#file_info.size]),
     ok = printfile(Data),
     ok.
-- 
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